New spectrophotometric method for estimation of losartan potassium using Alizarin Red reagent

Abstract

A simple, rapid, precise, and sensitive analytical method has been developed to identify losartan potassium in its pure and pharmaceutical dosage forms. This method involves a proton transfer between the losartan reagent and the Alizarin Red reagent in an acidic medium while standing to complete the reaction to obtain a colored product bound to the amount of losartan potassium, this product having a maximum absorption at 493 nm. A linear calibration curve was obtained over a concentration range of 1.5–12.5 gml–1 with a correlation coefficient of 0.9991. The molar absorptivity was 4.522104 lmol–1cm–1, and Sandell's sensitivity index was equal to 0.010 gcm–2. The limit of detection (LOD) and quantification (LOQ) values were 0.359 and 1.121 gml–1, respectively. The suggested approach was applied to estimate losartan potassium in the available pharmaceutical preparations (tablets). The results confirmed that the technique is successful by studying the recovery using the standard addition method.